This changes the default initialization of the EHCI "park" mode sothat silicon which supports it (NF2, NF3, ALI, GeneSys, ...) will notuse it unless explicitly told to do so by a (new) module parameter.

This is a workaround for some problems observed on some NF2 systems:

- Throughput ("hdparm -tT") is lower than expected with recent high performance drives (Maxtor) ... disabling "park" increases it by about 2 MByte/sec, but it's still much slower than expected. (USB analyser traces should be informative here.)

- Some data corruption observed on reads from drives using an ALI storage adapter ... disabling "park" stops the corruption. (Strongly suggestive of hardware or peripheral firmware bugs; multiple back-to-back bulk-IN packets should work just fine.)

The "don't use park mode" workaround will at most reduce USB (and PCI)throughput slightly on systems that work as expected, but some of thosecan re-enable the "park" mode.